Hi,
I am going to fit a Contax Zeiss 35mm f/1.4 MMJ on an EOS 5D MkII, and have been reading the "official thread". However, tips regarding 1.4/35 on 5D seems to be for either the Rollei version or the AE version. The MMJ has no screws (blue arrow) to adjust the focus/infinity setting. In addition to the retainment-ring-fin (green arrow), the MM also has a lever for the aperture (red arrow). In order for the mirror not to hit the lens, I guess I have to sand down both the "fin" and the "lever"? However, if I apply pressure to the lever, it may bend some internal structures - and perhaps destroy the function of the aperture? How did you guys get rid of the lever??

You don't have to completely remove the aperture lever. Shortening it a bit should be enough. You could use tin snips or a rotary cutter/Dremel to avoid putting too much pressure on the aperture lever.

Why don't you try mounting the lens with a regular C/Y to EF adapter? If the aperture lever protrudes too far you'll notice you can't close the aperture.

If you're going to sand down the protector fin, make sure you seal the lens very well with tape, so that you're not getting metal particles inside the lens and onto the rear lens.

The distance between the aperture-lever and the retainment-ring is very narrow, do not think I can get a tin snip in there... But is that what you did? Did you first bend it so you could snip it off?
Since I do not have a C/Y camera, the lever is useless to me - but I do not wanna damage something so the aperture may not work as it should. Maybe sanding is the best solution?

Like I said, it's not necessary to completely remove the lever. You probably just need to remove a bit off the top of the lever.
On most Contax lenses it's not necessary to remove it at all and they still work fine on a 5D (it's not in the way of anything at all). My Distagon 28/2.8 works fine without any modifications on my 5D, although some others have had mirror clearance problems with this lens. You just have to try it on an adapter before worrying.

The lever isn't totally worthless -- in case you decide to sell the lens again at some point, people will generally pay more for an unmodified lens.

As it turned out, I do not have a mirror problem. I am terribly ashamed by my mistake, lol. Having kids running around all over, I popped into the basement, and mounted the Leitax mount - then quickly mounted it on my 5DII, which had the mirror raised (live-view turned on). Then I turned live view off, but the view-finder was still black - thus the mirror must have hanged I thought. Turned out I had subconsiously put on the front cap...

So I can higly recommend the Leitax mount: it is cheaper than most adapters, it can focus to infinity, has no mirror problem, and is rock steady on the lens..

@John: You have rotational play with your adapter? With most adapters this is quite easy to fix, simply by wedging a small screw driver or knife between the bayonet lugs, to increase the pressure that the adapter puts on the Contax mount.

I'm also interested to hear how ceder Leitaxed his 35/1.4. Did you use the M42 solution?

@aham, I've done that but the adapter itself moves around the lense. I wish i had a video camera to show you. the best way i can describe is this analogy: imagine a large ring laying flat on the table, then put your finger in the ring..there is considerable gap between your finger and the inner circumference of the ring..while the adapter to the internal circum. of the 35 is not that substantial, i believe the weight of the 35 is causing the movement. I don't have this problem with my 50 1.4... I have the big_is and fotodiox adapters.. and its the same with both.

The Leitax conversion is dependent on the lens. However, most lenses are quite trivial. Usually, it is something like:

- unscrew some screws
- remove the old mount
- fiddle with aperture lever
- screw new mount on

and if you didn't pay for the pre-installed Dandelion chip, you might have to add that as well. My Contax 80-200/4 was quite a bit more complicated though, and David doesn't have instructions on the site for this lens yet. The 35-70/3.4 Nikon mount is even more difficult to do.

I understand what you're saying, John. Perhaps the same thing may happen with your 50/1.4, but only if you put some force on it (which isn't recommendable of course). I believe all adapters that I have used had a slightly larger inner diameter than all the different lenses I've used them with (except the Fotodiox Pro Mamiya 645 to EF adapter perhaps).

@ceder: So was it the "M42 solution" for the 35/1.4 that you used, or a Leitax Contax for Canon mount? I don't understand why the website can't be clearer about which mounts fit to which lenses. He must have received plenty of feedback by now about all the Contax lenses.